Dual Durometer Insulating Boot for Electrosurgical Forceps

ABSTRACT

An electrosurgical forceps includes a shaft having a pair of jaw members at a distal end and movable about a pivot from a first position and disposed in spaced relation relative to one another to a second position wherein the jaw members are closer to one another for grasping tissue, a movable handle that actuates a drive assembly to move the jaw members relative to one another. At least one jaw member conducts electrical energy to tissue held therebetween. A flexible insulating boot is disposed on an exterior surface of at least one jaw member and about the pivot and includes a first longitudinal portion made from a high durometer material and a second longitudinal portion made from a low durometer material. The high durometer material may operably retain the flexible insulating boot atop the proximal ends of the jaw members.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims the benefit of and priority to, U.S. patent application Ser. No. 12/212,333, filed on Sep. 17, 2008, “DUAL DUROMETER INSULATING BOOT FOR ELECTROSURGICAL FORCEPS”, by Guerra et al., published as U.S. Patent Application Publication No. US 2009/0088738 A1 on Apr. 2, 2009, and U.S. Provisional Patent Application No. 60/995,865 by Guerra et al., filed on Sep. 28, 2007, the entire contents of each of which is hereby incorporated by reference herein.

BACKGROUND

1. Technical Field

The present disclosure relates to an insulated electrosurgical forceps and more particularly, the present disclosure relates to an insulating boot for use with either an endoscopic or open bipolar and/or monopolar electrosurgical forceps for sealing, cutting, and/or coagulating tissue.

2. Background of Related Art

Electrosurgical forceps utilize both mechanical clamping action and electrical energy to effect hemostasis by heating the tissue and blood vessels to coagulate, cauterize and/or seal tissue. As an alternative to open forceps for use with open surgical procedures, many modern surgeons use endoscopes and endoscopic instruments for remotely accessing organs through smaller, puncture-like incisions. As a direct result thereof, patients tend to benefit from less scarring and reduced healing time.

Endoscopic instruments are inserted into the patient through a cannula, or port, which has been made with a trocar. Typical sizes for cannulas range from three millimeters to twelve millimeters. Smaller cannulas are usually preferred, which, as can be appreciated, ultimately presents a design challenge to instrument manufacturers who must find ways to make endoscopic instruments that fit through the smaller cannulas.

Many endoscopic surgical procedures require cutting or ligating blood vessels or vascular tissue. Due to the inherent spatial considerations of the surgical cavity, surgeons often have difficulty suturing vessels or performing other traditional methods of controlling bleeding, e.g., clamping and/or tying-off transected blood vessels. By utilizing an endoscopic electrosurgical forceps, a surgeon can either cauterize, coagulate/desiccate and/or simply reduce or slow bleeding simply by controlling the intensity, frequency and duration of the electrosurgical energy applied through the jaw members to the tissue. Most small blood vessels, i.e., in the range below two millimeters in diameter, can often be closed using standard electrosurgical instruments and techniques. However, if a larger vessel is ligated, it may be necessary for the surgeon to convert the endoscopic procedure into an open-surgical procedure and thereby abandon the benefits of endoscopic surgery. Alternatively, the surgeon can seal the larger vessel or tissue.

It is thought that the process of coagulating vessels is fundamentally different than electrosurgical vessel sealing. For the purposes herein, “coagulation” is defined as a process of desiccating tissue wherein the tissue cells are ruptured and dried. “Vessel sealing” or “tissue sealing” is defined as the process of liquefying the collagen in the tissue so that it reforms into a fused mass. Coagulation of small vessels is sufficient to permanently close them, while larger vessels need to be sealed to assure permanent closure.

A general issue with existing electrosurgical forceps is that the jaw members rotate about a common pivot at the distal end of a metal or otherwise conductive shaft such that there is potential for both the jaws, a portion of the shaft, and the related mechanism components to conduct electrosurgical energy (either monopolar or as part of a bipolar path) to the patient tissue. Existing electrosurgical instruments with jaws either cover the pivot elements with an inflexible shrink-tube or do not cover the pivot elements and connection areas and leave these portions exposed.

SUMMARY

An electrosurgical forceps includes a shaft having a pair of jaw members at a distal end thereof the jaw members movable about a pivot from a first position wherein the jaw members are disposed in spaced relation relative to one another to a second position wherein the jaw members are closer to one another for grasping tissue, a movable handle that actuates a drive assembly to move the jaw members relative to one another. At least one of the jaw members includes at least one mechanical interface and at least one jaw member is adapted to connect to a source of electrical energy such that the at least one jaw member is capable of conducting energy to tissue held therebetween. A flexible insulating boot is disposed on at least a portion of an exterior surface of at least one jaw member and about the pivot, the flexible boot including a first longitudinal portion made from a high durometer material and a second longitudinal portion made from a low durometer material. The high durometer material may be configured to operably retain the flexible insulating boot atop both the proximal ends of the jaw members.

The high durometer material may be disposed at a distal end of the flexible insulating boot, and may include an aperture defined therein which is configured to operably receive a proximal end of each jaw member therethrough.

Each jaw member may include a proximal flange associated therewith and the shaft may define an outer periphery, and wherein the low durometer material may stretch to allow the proximal flange of each jaw member to rotate beyond the outer periphery of the shaft.

The high durometer portion may include proximally-extending fingers which define upper and lower slots therein that are dimensioned to receive corresponding upper and lower low durometer portions during co-extrusion of the flexible insulating boot.

Each jaw member may include a proximal flange associated therewith and the shaft may define an outer periphery, and wherein the low durometer material may be oriented to stretch and allow the proximal flange of each jaw member to rotate beyond the outer periphery of the shaft.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the subject instrument are described herein with reference to the drawings wherein.

FIG. 1 is a left, perspective view including an endoscopic bipolar forceps showing a housing, a shaft and an end effector assembly having an insulating boot according to one embodiment of the present disclosure;

FIG. 2A is an enlarged, right perspective view of the end effector assembly with a pair of jaw members of the end effector assembly shown in open configuration having the insulating boot according to the present disclosure;

FIG. 2B is an enlarged, bottom perspective view of the end effector assembly with the jaw members shown in open configuration having the insulating boot according to the present disclosure;

FIG. 3 is a right, perspective view of another version of the present disclosure that includes an open bipolar forceps showing a housing, a pair of shaft members and an end effector assembly having an insulating boot according to the present disclosure;

FIG. 4A is an rear perspective view of the end effector assembly of FIG. 1 showing a pair of opposing jaw members in an open configuration;

FIG. 4B is an rear perspective view of the end effector assembly of FIG. 1 showing a pair of opposing jaw members in a closed configuration;

FIG. 4C is an side view of the end effector assembly of FIG. 1 showing the jaw members in a open configuration;

FIG. 5 is an enlarged, schematic side view of the end effector assembly showing one embodiment of the insulating boot configured as a mesh-like material;

FIG. 6A is an enlarged, schematic side view of the end effector assembly showing another embodiment of the insulating boot which includes an enforcement wire disposed longitudinally therealong which is dimensioned to strengthen the boot;

FIG. 6B is a front cross section along line 6B-6B of FIG. 6A;

FIG. 7 is an enlarged, schematic side view of the end effector assembly showing another embodiment of the insulating boot which includes wire reinforcing rings disposed at the distal end proximal ends thereof;

FIG. 8A is an enlarged view of a another embodiment of the insulating boot according to the present disclosure;

FIG. 8B is a front cross section along line 8B-8B of FIG. 8A FIG. 8C is an enlarged view of the insulating boot of FIG. 8A shown in a partially compressed orientation;

FIG. 8D is an enlarged side view of the end effector assembly shown with the insulating boot of FIG. 8A disposed thereon;

FIG. 8E is an enlarged side view of the end effector assembly shown with the insulating boot of FIG. 8A disposed thereon shown in a partially compressed orientation;

FIG. 9A is an enlarged view of another embodiment of the insulating boot according to the present disclosure including a mesh and silicone combination;

FIG. 9B is a greatly-enlarged, broken view showing the radial expansion of the mesh portion of the insulating boot of FIG. 9A when longitudinally compressed;

FIG. 10 is an enlarged view of another embodiment of the insulating boot according to the present disclosure including a detent and dollop of adhesive to provide mechanical retention of the insulating boot atop the forceps jaws;

FIG. 11 is an enlarged view of another embodiment of the insulating boot according to the present disclosure including a chamfer section which provides an inflow channel for the adhesive during curing;

FIG. 12 is an enlarged view of another embodiment of the insulating boot according to the present disclosure including an adhesive layer which seals the junction between the insulating boot and the jaw overmold;

FIG. 13 is an enlarged view of another embodiment of the insulating boot according to the present disclosure including a heat activated adhesive flow ring which facilitates adherence of the insulating boot to the jaw members;

FIG. 14 is an enlarged view of another embodiment of the insulating boot according to the present disclosure which includes a tape layer to hold the boot against the back of the jaw members;

FIG. 15A is an enlarged view of another embodiment of the insulating boot according to the present disclosure including a ring of elastomer connections which both transfer current and facilitate retention of the insulating boot atop the jaw members;

FIG. 15B is a front cross section along line 15B-15B of FIG. 15A;

FIG. 16 is an enlarged view of another embodiment of the present disclosure which includes an insulating sheath filled with silicone gel to facilitate insertion of the cannula within a body cavity;

FIG. 17A is an enlarged view of another embodiment of the present disclosure which includes a plastic shield overmolded atop the jaw members to insulate the jaw members from one another;

FIG. 17B is an enlarged view of a the two jaw members of FIG. 17A shown assembled;

FIG. 18A is an enlarged view of another embodiment of the present disclosure similar to FIGS. 17A and 17B wherein a weather stripping is utilized to seal the gap between jaw members when assembled;

FIG. 18B is a front cross section along line 18B-18B of FIG. 18A;

FIG. 19A is an enlarged view of another embodiment of the present disclosure which includes an insulating boot with a series of radially extending ribs disposed therearound to reduce surface friction of the insulating boot during insertion through a cannula;

FIG. 19B is a front cross section along line 19B-19B of FIG. 19A;

FIG. 20 is an enlarged view of another embodiment of the present disclosure wherein a soft, putty-like material acts as the insulator for the various moving parts of the jaw members;

FIG. 21 is an enlarged view of another embodiment of the present disclosure which includes an insulating shield disposed between the boot and the metal sections of the jaw members;

FIG. 22A is an enlarged view of another embodiment of the present disclosure which includes a plastic wedge disposed between the boot and the proximal end of the jaw members which allows the jaw members to pivot;

FIG. 22B is a cross section along line 22B-22B of FIG. 22A;

FIG. 23A is an enlarged view of another embodiment of the present disclosure which includes a silicone boot with a ring disposed therein which is composed of an adhesive material which actively fills any holes created by arcing high current discharges;

FIG. 23B is a cross section along line 23B-23B of FIG. 23A;

FIG. 24A is an enlarged view of another embodiment of the present disclosure which includes a silicone boot with an ring disposed therein which is composed of an insulative material which actively fills any holes created by arcing high current discharges;

FIG. 24B is a cross section along line 24B-24B of FIG. 24A;

FIG. 25 is an enlarged view of another embodiment of the present disclosure wherein a distal end of a shaft which is overmolded with a silicone material;

FIG. 26A is an enlarged view of another embodiment of the present disclosure which includes an insulating boot being made from a low durometer material and a high durometer material--the low durometer material being disposed about the moving parts of the jaw members;

FIG. 26B is a cross section along line 26B-26B of FIG. 26A;

FIG. 27 is an enlarged view of another embodiment of the present disclosure which includes an insulating ring being made from a high durometer material;

FIG. 28 is an enlarged view of another embodiment of the present disclosure which includes an insulating boot which is packaged with a cannula and designed for engagement over the jaw members when the jaw members are inserted into the cannula;

FIGS. 29A and 29B are enlarged views of other embodiments of the present disclosure which include an insulating boot having a tapered distal end;

FIG. 29C is an enlarged view of another embodiment of the present disclosure which includes an insulating boot having a square-like taper at the distal end;

FIG. 29D is an enlarged view of another embodiment of the present disclosure which includes an insulating boot having a square, tapered section;

FIG. 30 is an enlarged view of another embodiment of the present disclosure which includes an insulating boot having a detent in the jaw overmold which is designed to mechanically engage the insulating boot;

FIG. 31 is an enlarged view of another embodiment of the present disclosure which includes an insulating boot and a ring-like sleeve;

FIG. 32 is an enlarged view of another embodiment of the present disclosure which includes an insulating boot which includes a weather strip type mechanical interface disposed at the junction of the boot and the jaw members;

FIGS. 33A and 33B are enlarged views of another embodiment of the present disclosure which includes a co-molded boot having a silicone portion and proximal and side portions made of a thermoplastic material;

FIG. 34 is an enlarged view of another embodiment having a silicone boot with a plastic shell overlapped with a heat shrink tubing;

FIGS. 35A-35B is an enlarged view of another embodiment of the present disclosure including a thermoplastic clevis having a pair of fingers and which project inwardly to mechanically engage the proximal end of jaw members;

FIG. 36 is an enlarged view of another embodiment of the present disclosure which includes a silicone overmolded clevis similar to the embodiment of FIG. 38 which also includes a thermoplastic tube configured to encompass an endoscopic shaft member;

FIG. 37 is an enlarged view of another embodiment of the present disclosure with thermoplastic rails along a length thereof;

FIGS. 38A-38D are enlarged views of another embodiment of the present disclosure which includes an insulating boot with a ring-like mechanical interface which is configured to include a key-like interface for engaging the proximal ends of the jaw members;

FIGS. 39A-39D are enlarged views of another embodiment of the present disclosure which includes an insulating boot having a key-like interface disposed at a distal end thereof for engaging the proximal ends of the jaw members, the insulating boot being made from a low durometer material and a high durometer material;

FIG. 40 are enlarged views of another embodiment of the present disclosure which includes a plastic guard rail which secures the insulating boot to the jaw members and heat shrink material by a series of hook-like appendages;

FIG. 41 is an enlarged view of another embodiment of the present disclosure which includes an insulating boot having a series of pores defined in an outer periphery thereof, the pores having a heat activated lubricant disposed therein to facilitate insertion of the forceps within a cannula;

FIG. 42 is an enlarged view of another embodiment of the present disclosure which includes a heat-cured adhesive which is configured to mechanically engage and secure the insulating boot to the jaw members;

FIG. 43 is an enlarged view of another embodiment of the present disclosure which includes an insulating boot having an overlapping portion which engages and overlaps the jaw members, the jaw members including a hole defined therein which contains a glue which bonds to the overlapping portion of the insulating boot;

FIGS. 44A-44B are enlarged views of another embodiment of the present disclosure which includes an uncured adhesive sleeve which is configured to engage the distal end of the shaft and the jaw members and bond to the uninsulated parts when heated;

FIGS. 45A-45B are enlarged views of another embodiment of the present disclosure which includes an insulating boot having an uncured adhesive ring which is configured to bond and secure the insulating boot to the jaw members when heated; and

FIG. 46 is an enlarged view of another embodiment of the present disclosure which includes a coating disposed on the exposed portions of the jaw members, the coating being made from a material that increases resistance with heat or current.

DETAILED DESCRIPTION

Referring initially to FIGS. 1-2B, one particularly useful endoscopic forceps 10 is shown for use with various surgical procedures and generally includes a housing 20, a handle assembly 30, a rotating assembly 80, a trigger assembly 70 and an end effector assembly 100 that mutually cooperate to grasp, seal and divide tubular vessels and vascular tissue. For the purposes herein, forceps 10 will be described generally. However, the various particular aspects of this particular forceps are detailed in commonly owned U.S. patent applications Ser. No. 10/460,926, now U.S. Pat. No. 7,156,846 B2, “VESSEL SEALER AND DIVIDER FOR USE WITH SMALL TROCARS AND CANNULAS”, issued to Dycus et al. on Jan. 2, 2007, U.S. patent application Ser. No. 10/953,757, now U.S. Pat. No. 7,150,749 B2, “VESSEL SEALER AND DIVIDER HAVING ELONGATED KNIFE STROKE AND SAFETY CUTTING MECHANISM”, issued to Dycus et al. on Dec. 19, 2006, and U.S. patent application Ser. No. 11/348,072, now U.S. Pat. No. 7,771,425 B2, “VESSEL SEALER AND DIVIDER HAVING A VARIABLE JAW CLAMPING MECHANISM”, issued to Dycus et al. on Aug. 10, 2010.

Forceps 10 also includes a shaft 12 that has a distal end 16 dimensioned to mechanically engage the end effector assembly 100 and a proximal end 14 that mechanically engages the housing 20 through rotating assembly 80. As will be discussed in more detail below, the end effector assembly 100 includes a flexible insulating boot 500 configured to cover at least a portion of the exterior surfaces of the end effector assembly 100.

Forceps 10 also includes an electrosurgical cable 310 that connects the forceps 10 to a source of electrosurgical energy, e.g., a generator (not shown). The generator includes various safety and performance features including isolated output, independent activation of accessories, and Instant Response™ technology (a proprietary technology of Valleylab, Inc., a division of Tyco Healthcare, LP) that provides an advanced feedback system to sense changes in tissue many times per second and adjust voltage and current to maintain appropriate power. Cable 310 is internally divided into a series of cable leads (not shown) that each transmit electrosurgical energy through their respective feed paths through the forceps 10 to the end effector assembly 100.

Handle assembly 30 includes a two opposing handles 30 a and 30 b which are each movable relative to housing 20 from a first spaced apart position wherein the end effector is disposed in an open position to a second position closer to housing 20 wherein the end effector assembly 100 is positioned to engage tissue. Rotating assembly 80 is operatively associated with the housing 20 and is rotatable in either direction about a longitudinal axis “A” (See FIG. 1). Details of the handle assembly 30 and rotating assembly 80 are described in the above-referenced patent applications, namely, U.S. patent applications Ser. No. 10/460,926, now U.S. Pat. No. 7,156,846 B2, U.S. patent application Ser. No. 10/953,757, now U.S. Pat. No. 7,150,749 B2, and U.S. patent application Ser. No. 11/348,072, now U.S. Pat. No. 7,771,425 B2.

As mentioned above and as shown best in FIGS. 2A and 2B, end effector assembly 100 is attached at the distal end 14 of shaft 12 and includes a pair of opposing jaw members 110 and 120. Opposing handles 30 a and 30 b of handle assembly 30 are ultimately connected to a drive assembly (not shown) that, together, mechanically cooperate to impart movement of the jaw members 110 and 120 from an open position wherein the jaw members 110 and 120 are disposed in spaced relation relative to one another, to a clamping or closed position wherein the jaw members 110 and 120 cooperate to grasp tissue therebetween. All of these components and features are best explained in detail in the above-identified commonly owned U.S. application Ser. No. 10/460,926, now U.S. Pat. No. 7,156,846 B2.

FIG. 3 shows insulating boot 500 configured to engage a forceps 400 used in open surgical procedures. Forceps 400 includes elongated shaft portions 412 a and 412 b having an end effector assembly 405 attached to the distal ends a and 416 b of shafts 412 a and 412 b, respectively. The end effector assembly 405 includes pair of opposing jaw members 410 and 420 which are pivotably connected about a pivot pin 465 and which are movable relative to one another to grasp tissue.

Each shaft 412 a and 412 b includes a handle 415 a and 415 b, respectively, disposed at the proximal ends thereof. As can be appreciated, handles 415 a and 415 b facilitate movement of the shafts 412 a and 412 b relative to one another which, in turn, pivot the jaw members 410 and 420 from an open position wherein the jaw members 410 and 420 are disposed in spaced relation relative to one another to a clamping or closed position wherein the jaw members 410 and 420 cooperate to grasp tissue therebetween. Details relating to the internal mechanical and electromechanical components of forceps 400 are disclosed in commonly-owned U.S. patent application Ser. No. 10/962,116, now U.S. Pat. No. 7,811,283 B2, “OPEN VESSEL SEALING INSTRUMENT WITH HOURGLASS CUTTING MECHANISM AND OVER-RATCHET SAFETY”, issued to Moses et al. on Oct. 12, 2010. As will be discussed in more detail below, an insulating boot 500 or other type of insulating device as described herein may be configured to cover at least a portion of the exterior surfaces of the end effector assembly 405 to reduce stray current concentrations during electrical activation.

As best illustrated in FIG. 3, one of the shafts, e.g., 412 b, includes a proximal shaft connector 470 which is designed to connect the forceps 400 to a source of electrosurgical energy such as an electrosurgical generator (not shown). The proximal shaft connector 470 electromechanically engages an electrosurgical cable 475 such that the user may selectively apply electrosurgical energy as needed. The cable 470 connects to a handswitch 450 to permit the user to selectively apply electrosurgical energy as needed to seal tissue grasped between jaw members 410 and 420. Positioning the switch 450 on the forceps 400 gives the user more visual and tactile control over the application of electrosurgical energy. These aspects are explained below with respect to the discussion of the handswitch 450 and the electrical connections associated therewith in the above-mentioned commonly-owned U.S. patent application Ser. No. 10/962,116, now U.S. Pat. No. 7,811,283 B2.

A ratchet 430 is included which is configured to selectively lock the jaw members 410 and 420 relative to one another in at least one position during pivoting. A first ratchet interface 431 a extends from the proximal end of shaft member 412 a towards a second ratchet interface 431 b on the proximal end of shaft 412 b in general vertical registration therewith such that the inner facing surfaces of each ratchet 431 a and 431 b abut one another upon closure of the jaw members 410 and 420 about the tissue. The ratchet position associated with the cooperating ratchet interfaces 431 a and 431 b holds a specific, i.e., constant, strain energy in the shaft members 412 a and 412 b which, in turn, transmits a specific closing force to the jaw members 410 and 420.

The jaw members 410 and 420 are electrically isolated from one another such that electrosurgical energy can be effectively transferred through the tissue to form a tissue seal. Jaw members 410 and 420 both include a uniquely-designed electrosurgical cable path disposed therethrough which transmits electrosurgical energy to electrically conductive sealing surfaces 412 and 422, respectively, disposed on the inner facing surfaces of jaw members, 410 and 420.

Turning now to the remaining figures, FIGS. 4A-46, various envisioned embodiments of electrical insulating devices are shown for shielding, protecting or otherwise limiting or directing electrical currents during activation of the forceps 10, 400. More particularly, FIGS. 4A-4C show one embodiment wherein the proximal portions of the jaw members 110 and 120 and the distal end of shaft 12 are covered by the resilient insulating boot 500 to reduce stray current concentrations during electrosurgical activation especially in the monopolar activation mode. More particularly, the boot 500 is flexible from a first configuration (See FIG. 4B) when the jaw members 110 and 120 are disposed in a closed orientation to a second expanded configuration (See FIGS. 4B and 4C) when the jaw members 110 and 120 are opened. When the jaw members 110 and 120 open, the boot flexes or expands at areas 220 a and 220 b to accommodate the movement of a pair of proximal flanges 113 and 123 of jaw members 110 and 120, respectively (see FIGS. 17A and 17B). Further details relating to one envisioned insulating boot 500 are described with respect to commonly-owned U.S. application Ser. No. 11/529,798 entitled “INSULATING BOOT FOR ELECTROSURGICAL FORCEPS”, ”, now U.S. Pat. No. 7,846,161 B2 issued to Dumbauld et al. on Dec. 7, 2010, the entire contents of which being incorporated by reference herein.

FIG. 5 shows another embodiment of an insulating boot 600 which is configured to reduce stray current concentrations during electrical activation of the forceps 10. More particularly, the insulating boot 600 includes a woven mesh 620 which is positioned over a proximal end of the jaw members 110 and 120 and a distal end of the shaft 12. During manufacturing, the mesh 620 is coated with a flexible silicone-like material 610 which is designed to limit stray currents from emanating to surrounding tissue areas. The woven mesh 620 is configured to provide strength and form to the insulating boot 600. The woven mesh 620 is also configured to radially expand when the mesh 620 longitudinally contracts (See FIGS. 9A and 9B).

FIGS. 6A and 6B show another embodiment of an insulating boot 700 which includes a pair of longitudinally extending wires 720 a and 720 b encased within corresponding channels 710 a and 710 b, respectively, defined within the boot 700. The wires 720 a and 720 b re-enforce the boot 700 and may be manufactured from conductive or non-conductive materials. As can be appreciated, any number of wires 720 a and 720 b may be utilized to support the insulating boot 700 and enhance the fit of the boot 700 atop the jaw members 110 and 120. The wires 720 a and 720 b may be adhered to an outer periphery of the boot 700, adhered to an inner periphery of the boot 700, recessed within one or more channels disposed in the outer or inner periphery of the boot 700 or co-extruded or insert-molded into the insulating boot 700. The wires 720 a and 720 b may be manufactured from a flexible metal, surgical stainless steel, NiTi, thermoplastic, polymer, high durometer material and combinations thereof.

FIG. 7 shows another embodiment of an insulating boot 800 which includes a pair of circumferential wires 820 a and 820 b disposed within or atop the boot 800. The wires 820 a and 820 b re-enforce the boot 700 at the proximal and distal ends thereof and may be manufactured from conductive or non-conductive materials such as flexible metals, surgical stainless steel, NiTi, thermoplastic and polymers. Due to the tensile strength of the wires 820 a and 820 b, the boot 800 stays in place upon insertion though a cannula and further prevents the boot 800 from rolling onto itself during repeated insertion and/or withdrawal from a cannula. As can be appreciated, any number of wires 820 a and 820 b may be utilized to support the insulating boot 800 and enhance the fit of the boot atop the jaw members 110 and 120. For example, in one embodiment, the wires are insert molded to the boot 800 during a manufacturing step.

FIGS. 8A-8E show yet another embodiment of an insulating boot 900 which includes a molded thermoplastic shell 905 having a series of slits 930 a -930 d disposed therethrough which are configured to flex generally outwardly (See FIGS. 8C and 8E) upon the travel of the forceps shaft 12 to actuate the jaw members 110 and 120 to the open configuration. Shell 905 includes an inner periphery thereof lined with a silicone-like material 910 a and 910 b which provides patient protection from electrosurgical currents during activation while outer thermoplastic shell 905 protects the silicone material 910 a and 910 b during insertion and retraction from a surgical cannula (not shown). The outer shell 905 and the silicone-like material 910 a and 910 b may be overmolded or co-extruded during assembly.

As mentioned above, the outer shell 905 expands at expansion points 935 a and 935 b upon contraction of the shaft 12 or movement of the jaw members 110 and 120. During expansion of the shell 905, the shell 905 does not adhere to the inner silicone material 910 a and 910 b due the inherent properties of the silicone material 910 a and 910 b and selective texturing thereof. Shell 905 may also include an inner rim or latching areas 915 a and 915 b disposed at the distal (and/or proximal) end thereof. The latching areas 915 a and 915 b are configured to mechanically interface with the jaw members 110 and 120 and hold the shell 905 in place during relative movement of the shaft 12. Other mechanical interfaces 908 may also be included which are configured to engage the shell 905 with the jaw members and/or shaft 12, e.g., adhesive. The outer shell 905 may include a relief section 911 to facilitate engagement of the outer shell 905 atop the jaw members 110 and 120.

FIGS. 9A and 9B show yet another embodiment of the insulating boot 1000 which is configured to include an insulative mesh 1010 disposed at one end of boot 1000 and a silicone (or the like) portion 1020 disposed at the other end thereof. Mesh portion 1010 is configured to radially expand and longitudinally contract from a first configuration 1010 to a second configuration 1010′ as shown in FIG. 9B. The mesh portion 1010 is typically associated with the part of the boot closest to the jaw members 110 and 120.

FIG. 10 shows yet another embodiment of the insulating boot 1100 which is configured to mechanically engage a corresponding mechanical interface 1110 (e.g., detent or bump) disposed on a proximal end of the jaw members, e.g., jaw member 110. An adhesive 1120 may also be utilized to further mechanical retention. The at least one mechanical interface 1110 may also include a raised protuberance, flange, spike, cuff, rim, bevel and combinations thereof. The mechanical interface 1110 may be formed by any one of several known processes such as co-extrusion and overmolding.

Similarly, one or both jaw members 110 and 120 may include an underlapped or chamfered section 1215 which enhances mechanical engagement with the insulating boot 1200. For example and as best shown in FIG. 11, an adhesive 1210 may be utilized between the beveled section 1215 defined in jaw member 110 and the insulating boot 1200 to enhance mechanical engagement of the boot 1200. Further and as best shown in FIG. 12, an adhesive 1410 may be disposed atop the intersection or abutment of the bevel 1415 and insulating boot 1400 to further mechanical retention of the boot 1400. The adhesive 1410 may be configured to cure upon application of heat, ultraviolet light, electrical energy or other ways customary in the trade.

FIG. 13 shows yet another embodiment of an insulating boot 1300 which includes an internally-disposed glue ring 1310 disposed along the inner periphery 1320 of the boot 1300. The glue ring 1310 is configured to cure when heated or treated with light (or other energy) depending upon a particular purpose or manufacturing sequence.

FIG. 14 shows yet another embodiment of an insulating boot 1500 which is configured to cooperate with a glue-like tape 1510 which holds the distal end 1515 of the insulating boot 1500 in place atop the proximal ends 111 and 121 of the jaw members 110 and 120, respectively. Tape 1510 may be configured to cure upon application of heat or other energy. The tape 1510 may also be configured to include an aperture 1511 defined therein which is dimensioned to receive the proximal end of the jaw members 110 and 120.

FIGS. 15A and 15B show yet another embodiment of an insulating boot 1600 which includes a series of electrical leads 1610 a -1610 h disposed therethrough which are designed to electromechanically engage the jaw members 110 and 120 and supply current thereto. More particularly, boot 1600 may include leads 1610 a -1610 d which carry on electrical potential to jaw member 110 and leads 1610 e-1610 h which are designed to carry a second electrical potential to jaw member 120. The leads 1610 a -1610 h may be configured as metal strands disposed along the inner peripheral surface of boot 1600 which are configured to provide electrical continuity to the jaw members 110 and 120. The leads 1610 a -1610 f may be co-extruded or insert molded to the inner periphery of the boot 1600. At least one of the leads 1610 a -1610 h may be configured to carry or transmit a first electrical potential and at least one of the leads 1610 a -1610 h may be configured to carry a second electrical potential.

FIG. 16 shows yet another version of an insulating sheath or boot 1700 which is configured to be removable prior to insertion through a cannula (not shown). Boot 1700 is designed like a condom and is filled with a silicone lube 1710 and placed over the distal end of jaw members 110 and 120. Prior to insertion of the forceps 10 through a cannula, the boot 1700 is removed leaving residual silicone 1710 to facilitate insertion through the cannula. The forceps 10 may also include a second insulating boot 500 to reduce current concentrations similar to any one of the aforementioned embodiments or other embodiments described herein.

The present disclosure also relates to a method of facilitating insertion of a forceps through a cannula and includes the steps of providing a forceps including a shaft having a pair of jaw members at a distal end thereof. The jaw members are movable about a pivot from a first position wherein the jaw members are disposed in spaced relation relative to one another to a second position wherein the jaw members are closer to one another for grasping tissue. At least one of the jaw members is adapted to connect to a source of electrical energy such that the at least one jaw member is capable of conducting energy to tissue held therebetween. An insulative sheath is disposed atop at least a portion of an exterior surface of at least one jaw member, about the pivot and the distal end of the shaft. The insulative sheath houses a silicone lube configured to facilitate insertion of the forceps through a cannula after removal of the insulative sheath.

The method also includes the steps of removing the insulative sheath to expose the silicone lube atop the exterior surface of at least one jaw member, about the pivot and the distal end of the shaft, engaging the forceps for insertion through a cannula and inserting the forceps through the cannula utilizing the silicone lube to facilitate insertion.

FIGS. 17A and 17B show still another embodiment of the insulating boot 1800 which is configured as elastomeric shields 1800 a and 1800 b which are overmolded atop the proximal ends of respective jaw members 110 and 120 during a manufacturing step. A retention element (e.g., mechanical interface 1110) may also be included which engages one or both shields 1800 a, 1800 b. Once the forceps 10 is assembled, the elastomeric shields 1800 a and 1800 b are configured to abut one another to reduce stray current concentrations. FIGS. 18A and 18B show a similar version of an insulating boot 1900 which includes two overmolded elastomeric shields 1900 a and 1900 b which are mechanically engaged to one another by virtue of one or more weather strips 1910 a and 1910 b. More particularly, the weather strips 1910 a and 1910 b are configured to engage and seal the two opposing shields 1900 a and 1900 b on respective jaw members 110 and 120 during the range of motion of the two jaw members 110 and 120 relative to one another.

FIGS. 19A and 19B show yet another embodiment of the insulating boot 2000 which includes an elastomeric or silicone boot similar to boot 500 wherein the outer periphery of the boot 2000 includes a plurality of ribs 2010 a -2010 h which extend along the length thereof. It is contemplated that the ribs 2010 a -2010 h reduce the contact area of the boot 2000 with the inner periphery of a cannula (not shown) to reduce the overall surface friction of the boot during insertion into and withdrawal from the cannula.

FIG. 20 shows still another embodiment of the insulating boot 2100 which includes a soft caulk or putty-like material 2110 formed atop or within the boot which is configured to encapsulate the moving parts of the forceps 10. As best shown in FIG. 21, an overmolded section 114′ may be formed over the proximal flange 113 of the jaw members, e.g., jaw member 110, to provide a rest for the insulating boot 500 (or any other version described above).

FIGS. 22A and 22B show yet another embodiment of an insulating boot 2200 which includes a plastic wedge-like material 2210 formed between the boot 2200 and the proximal ends 110′ and 120′ of the jaw members, e.g., jaw member 110 and jaw member 120, respectively. As best illustrated in the cross-section view of FIG. 22B, the plastic wedge-like material forms an upper wedge 2210 a and a lower wedge 2210 b that are configured to allow a range of motion of the jaw members 110 and 120 while keeping the boot 2200 intact atop the shaft 12 and the moving flanges 113 and 123 of the jaw members 110 and 120, respectively.

FIGS. 23A and 23B show still another envisioned embodiment of an insulating boot 2300 which includes an outer silicone-like shell 2310 which is dimensioned to house a layer of high resistance adhesive material 2320. If high current flowing through the insulating boot 2300 causes a rupture in the boot 2300, the adhesive material 2320 melts and flows through the ruptured portion to reduce the chances of current leakage during activation. FIGS. 24A and 24B show a similar insulative boot 2400 wherein the insulative boot 2400 includes a free flowing material which is designed to flow through the ruptured portion to provide additional insulation from current during activation. More particularly, the boot 2400 includes an internal cavity 2410 defined therein which retains a free-flowing material 2420. The free-flowing material 2420 is configured to disperse from the internal cavity 2410 when ruptured. The free-flowing material 2420 may be a high resistive adhesive, a lubricating material or an insulating material or combinations thereof. The internal cavity 2410 may be annular and disposed on a portion or the boot 2400 or may be longitudinal and disposed along a portion of the boot 2400. The free-flowing material 2420 may be configured to change state between a solid state and a liquid state upon the application of energy (e.g., heat energy) or light (e.g., ultraviolet). The free-flowing material 2420 may be disposed on either the distal and/or proximal ends of the flexible insulating boot 2400.

FIG. 25 shows yet another embodiment of the insulating boot 2500 wherein the distal end of the shaft 12 and the jaw members 110 and 120 are overmolded during manufacturing with a silicone material (or the like) to protect against stray current leakage during activation.

FIGS. 26A, 26B and 27 show other embodiments of insulating boots 2600 and 2700, respectively, wherein boots 2600 and 2700 include low durometer portions and high durometer portions. The boots 2600 and 2700 may be formed from a two-shot manufacturing process. More particularly, FIGS. 26A and 26B include a boot 2600 with a high durometer portion 2610 having an elongated slot of low durometer material 2620 disposed therein or therealong. The low durometer portion 2620 is dimensioned to encapsulate the moving flanges 113 and 123 of the jaw members 110 and 120, respectively. FIG. 27 shows another embodiment wherein a ring of high durometer material 2710 is disposed at the distal end of the boot 2700 for radial retention of the jaw members 110 and 120. The remainder of the boot 2700 consists of low durometer material 2720.

FIG. 28 shows another embodiment of the present disclosure wherein the insulating boot 2800 may be packaged separately from the forceps 10 and designed to engage the end of the shaft 12 and jaw members 110 and 120 upon insertion though a cannula 2850. More particularly, boot 2800 may be packaged with the forceps 10 (or sold with the cannula 2850) and designed to insure 90 degree insertion of the forceps 10 through the cannula 2850. The boot 2800 in this instance may be made from silicone, plastic or other insulating material.

FIGS. 29A-29D include various embodiments of a boot 2900 having a tapered distal end 2920 and a straight proximal end 2910. More particularly, FIG. 29A shows a tapered bottle-like distal end 2920 which is configured to provide enhanced retentive force at the distal end of the forceps 10 which reduces the chances of the boot 2900 slipping from the boot's 2900 intended position. FIG. 29B shows another version of the tapered boot 2900′ which includes a sharply tapered distal end 2920′ and a straight proximal end 2910′. FIG. 29C shows another boot 2900″ which includes a square-like taper 2920″ at the distal end thereof and a straight proximal end 2910″. FIG. 29D shows yet another version of a tapered boot 2900′″ which includes a square, tapered section 2930′″ disposed between distal and proximal ends, 2920′″ and 2910′″, respectively. The outer diameter of the insulating boot 2900 or the inner periphery of the insulating boot 2900 may include the tapered section.

FIG. 30 shows yet another embodiment of the presently disclosed boot 3000 which is configured to be utilized with a jaw member 110 having a proximal overmolded section 114′ similar to the jaw members disclosed with respect to FIG. 21 above. More particularly, jaw member 110 includes proximal overmolded section 114′ having a bump or protrusion 115′ disposed thereon. Bump 115′ is configured to mechanically cooperate with a corresponding portion 3010 of boot 3000 to enhance retention of the boot 3000 atop the jaw member 110.

FIG. 31 shows still another embodiment of an insulating boot 500 which includes a silicone (or similar) ring-like sleeve 3100 which is configured to engage and secure the boot 500 atop the shaft 12. FIG. 32 shows a similar boot 500 configuration wherein a pair of weather strips 3200 a and 3200 b are positioned to secure the boot 500 at the junction point between the end of shaft 12 and the proximal end of the jaw members 110 and 120.

FIGS. 33A-33B show yet another embodiment of a co-molded boot 3300 having a silicone portion 3305 and proximal and side portions 3310c, 3310 a and 3310 b made of a thermoplastic material (or the like). The thermoplastic materials 3310 a -3310 c enhance the rigidity and durability of the boot 3300 when engaged atop the jaw members 110 and 120 and the shaft 12. Thermoplastic portions 3310 a and 3310 b may be dimensioned to receive and/or mate with the proximal flanges 113 and 123 of j aw members 110 and 120, respectively.

FIG. 34 shows yet another embodiment of an insulating boot having a silicone boot 3350 mounted under a plastic shell 3355. A heat shrink tubing (or the like) 3360 is included which overlaps at least a portion of the plastic shell 3355 and silicone boot 3350.

FIGS. 35A and 35B show still another embodiment of an insulating boot 3400 which includes an overmolded thermoplastic clevis 3410 disposed on an inner periphery thereof which is configured to enhance the mechanical engagement of the boot 3400 with the jaw members 110 and 120 and shaft 12. More particularly, the clevis 3410 includes a pair of fingers 3410 a and 3410 b which project inwardly to mechanically engage the proximal end of jaw members 110 and 120. The proximal end of the boot 3400 fits atop the end of shaft 12 much like the embodiments described above (See FIG. 35B). An outer shell 3402 is disposed atop the overmolded thermoplastic clevis 3410 to enhance the rigidity of the boot 3400. The clevis 3410 includes a channel 3412 defined between the two fingers 3410 a and 3410 b which facilitates movement of the jaw members 110 and 120.

FIG. 36 shows yet another embodiment of an insulating boot 3500 which is similar to boot 3400 described above with respect to FIGS. 35A and 35B and includes a thermoplastic clevis 3510 having a pair of fingers 3510 a and 3510 b which project inwardly to mechanically engage the proximal end of jaw members 110 and 120. Boot 3500 also includes outer thermoplastic portions 3520 a and 3520 b which are configured to further enhance the rigidity of the boot 3500 and act as a so-called “exoskeleton”. A channel 3515 is defined between in the outer exoskeleton to facilitate movement of the jaw members 110 and 120. The two outer portions 3520 a and 3520 b also include a relief portion 3525 disposed therebetween which allows the boot 3500 to expand during the range of motion of jaw members 110 and 120.

FIG. 37 shows yet another embodiment of an insulating boot 3600 which includes a plurality of thermoplastic rails 3610 a -3610 d disposed along the outer periphery thereof. The rails 3610 a -3610 d may be formed during the manufacturing process by overmolding or co-extrusion and are configured to enhance the rigidity of the boot 3600 similar to the embodiment described above with respect to FIG. 19B.

FIGS. 38A-38D show still another embodiment of an insulating boot 3700 which includes a low durometer portion 3725 generally disposed at the proximal end 3720 thereof and a high durometer portion 3730 generally disposed at the distal end 3710 thereof. The high durometer portion 3730 may be configured to mechanically engage the low durometer portion 3725 or may be integrally associated therewith in a co-molding or over-molding process. The inner periphery 3750 of the high durometer portion 3730 is dimensioned to receive the flanges 113 and 123 of jaw members 110 and 120, respectively. The low durometer portion 3725 may be dimensioned to allow the proximal ends 113 and 123 of flanges to flex beyond the outer periphery of the shaft 12 during opening of the jaw members 110 and 120. It is also contemplated that the high durometer portion 3730 (or a combination of the high durometer portion 3730 and the low durometer portion 3725) may act to bias the jaw members 110 and 120 in a closed orientation.

FIGS. 39A-39D show yet another embodiment of an insulating boot 3800 which includes a low durometer portion 3825 and a high durometer portion 3830 generally disposed at the distal end 3810 thereof. The high durometer portion 3830 includes proximally-extending fingers 3820 a and 3820 b which define upper and lower slots 3840 a and 3840 b, respectively, dimensioned to receive upper and lower low durometer portions 3825 a and 3825 b, respectively. The inner periphery 3850 of the high durometer portion 3830 is dimensioned to receive flanges 113 and 123 of jaw members 110 and 120, respectively. It is also contemplated that the high durometer portion 3830 (or a combination of the high durometer portion 3830 and the low durometer portions 3825 a and 3825 b ) may act to bias the jaw members 110 and 120 in a closed orientation.

FIG. 40 shows yet another version of an insulating boot 3900 which includes a pair of hook-like mechanical interfaces 3900 a and 3900 b which are designed to engage the jaw members 110 and 120 at one end (e.g., the hook ends 3905 a and 3905 b) and designed to engage the shaft 12 at the opposite ends 3908 a and 3908b, respectively. More particularly, the boot 3900 includes a pair of rails or slots 3912 a and 3912 b defined in an outer periphery thereof which are dimensioned to receive the corresponding hook-like mechanical interfaces 3900 a and 3900 b therealong. The proximal ends 3908 a and 3908 b of the hook-like mechanical interfaces 3900 a and 3900 b are configured to secure about the shaft 12 during an initial manufacturing step and then are held in place via the employment of heat shrink wrapping 12′. The heat shrink wrapping 12′ prevents the hook-like mechanical interfaces 3900 a and 3900 b from slipping during insertion and removal of the forceps 10 through a cannula.

FIG. 41 shows still another version of an insulating boot 4000 which includes a series of pores 4010 a -4010 f disposed along the outer periphery thereof. A heat-activated adhesive or lubricant 4030 is included in the pores 4010 a -4010 f such that when the lubricant 4030 is heated, the lubricant 4030 flows freely over the boot 4000 thereby facilitating insertion and withdrawal of the forceps 10 from a cannula.

FIG. 42 shows still another embodiment of an insulating boot 500 which includes a strip of heat activated adhesive 4100 to secure the boot 500 to the jaw members 110 and 120. The heat activated adhesive 4100 is designed to cure upon the application of heat to prevent unwanted motion between the two jaw members 110 and 120 or between the jaw members 110 and 120 and the shaft 12. FIG. 43 shows a similar concept which includes an insulating boot 4200 having a pair of overlapping flanges 4220 a and 4220 b which extend toward the jaw members 110 and 120 and which cooperate with one or more apertures (not shown) defined in the proximal flanges 113 and 123 of the jaw members 110 and 120 to retain a heat-activated adhesive 4230 therein. Once heated, the adhesive 4230 cures and maintains a strong, low profile bond between the boot 4200 and the jaw members 110 and 120.

FIGS. 44A and 44B show still another embodiment of an insulating boot 4300 which involves a two-step process for deployment atop the jaw members 110 and 120. During an initial manufacturing step the boot 4300 is in the form of an uncured adhesive sleeve 4300 and is fitted atop the proximal ends of the jaw members 110 and 120 and the shaft 12. Once properly positioned, the uncured adhesive sleeve 4300 is then cured using heat or UV light such that the cured boot 4300′ creates a conformal coating atop the jaw members 110 and 120 and acts to secure the boot 4300′ to the jaw members 110 and 120 and shaft 12 and insulate the surrounding tissue from negative electrical and thermal effects.

FIGS. 45A and 45B show still another embodiment of an insulating boot 4400 which also involves a two-step process for deployment atop the jaw members 110 and 120. During an initial manufacturing step the boot 4400 includes a ring of uncured adhesive material 4410 disposed along an inner periphery thereof. The boot 4400 with the uncured adhesive ring 4410 is fitted atop the proximal ends of the jaw members 110 and 120 and the shaft 12. Once properly positioned, the uncured adhesive ring 4410 is then cured using heat or UV light such that the cured boot 4400′ conforms atop the jaw members 110 and 120 and acts to secure the boot 4400′ to the jaw members 110 and 120 and shaft 12.

FIG. 46 shows still another embodiment of the present disclosure which includes a coating 110′ and 120′ disposed on the exposed portions of the jaw members 110 and 120. The coating 110′ and 120′ may be made from an insulating material or made from a material that increases resistance with heat or current. The tip portion 111 of the jaw members 110 is exposed and does not include the coating material such that electrosurgical energy may be effectively transferred to tissue via the exposed tip portion 111.

As mentioned above, the insulating boot 500 may be from any type of visco-elastic, elastomeric or flexible material that is biocompatible and that is configured to minimally impede movement of the jaw members 110 and 120 from the open to closed positions. The insulating boot 1500 may also be made at least partially from a curable material which facilitates engagement atop the jaw members 110 and 120 and the shaft 12. The presently disclosed insulating boots 500-4400′ described herein above may also be utilized with any of the forceps designs mentioned above for use with both endoscopic surgical procedures and open surgical procedures and both bipolar electrosurgical treatment of tissue (either by vessel sealing as described above or coagulation or cauterization with other similar instruments) and monopolar treatment of tissue.

The aforedescribed insulating boots, e.g., boot 500, unless otherwise noted, are generally configured to mount over the pivot, connecting jaw member 110 with jaw member 120. The insulating boots, e.g., boot 500, is flexible to permit opening and closing of the jaw members 110 and 120 about the pivot.

From the foregoing and with reference to the various figure drawings, those skilled in the art will appreciate that certain modifications can also be made to the present disclosure without departing from the scope of the same. For example and although the general operating components and inter-cooperating relationships among these components have been generally described with respect to a vessel sealing forceps, other instruments may also be utilized that may be configured to include any of the aforedescribed insulating boots to allow a surgeon to safely and selectively treat tissue in both a bipolar and monopolar fashion. Such instruments include, for example, bipolar grasping and coagulating instruments, cauterizing instruments, bipolar scissors, etc.

Furthermore, those skilled in the art recognize that while the insulating boots described herein are generally tubular, the cross-section of the boots may assume substantially any shape such as, but not limited to, an oval, a circle, a square, or a rectangle, and also include irregular shapes necessary to cover at least a portion of the jaw members and the associated elements such as the pivot pins and jaw protrusions, etc.

While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as exemplifications of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto. 

1.-7. (canceled)
 8. An electrosurgical forceps, comprising: a shaft having a pair of jaw members at a distal end thereof, the jaw members being movable about a pivot from a first position wherein the jaw members are disposed in spaced relation relative to one another to a second position wherein the jaw members are closer to one another for grasping tissue, at least one jaw member adapted to connect to a source of electrical energy and such that the jaw members are capable of conducting energy to tissue held therebetween; a movable handle that actuates a drive assembly to move the jaw members relative to one another; at least one of the jaw members including at least one mechanical interface and at least one jaw member being adapted to connect to a source of electrical energy; and a flexible insulating boot disposed on at least a portion of an exterior surface of at least one jaw member and about the pivot, the flexible boot including a first longitudinal portion made from a high durometer material and a second longitudinal portion made from a low durometer material, the high durometer portion including proximally-extending fingers which define upper and lower slots therein dimensioned to receive corresponding upper and lower low durometer portions during co-extrusion of the flexible insulating boot.
 9. An electrosurgical forceps according to claim 8 wherein each jaw member includes a proximal flange associated therewith and the shaft defines an outer periphery and wherein the low durometer material is oriented to stretch and allow the proximal flange of each jaw member to rotate beyond the outer periphery of the shaft. 